Process of refining marine oils



Patented July 31, 1945 Loran 0. Buxton, Newark, N. 1., minor to National Oil Products Company, Harrison, N. J., a corporation of New-Jersey No Drawing. Application July 13, 1942, Serial No, 450,762

9 Claims. (01.260-426) This invention relates to a new and improved process for refining fatty materials, particularly vitamin-containing oils of marine origin.

The treatment of fatty materials with a small amount of caustic alkali, commonly termed a1- kali refining, in order to refine the same has been practiced for many years. This process has certain major disadvantages. The treatment invariably fails to remove all of the undesirable -taste, color and odor associated with the crude fatty materials and in certain instances, particularly in the case of fatty materials of fish origin, the caustic alkali has a harmful effect on certain in most instances alarger proportion of the fatty material is saponified than in the usual alkali refining processes. By so doi the uncle-1 sirable constituents of the fatty material will be removed to a greater extent than in such processes and those undesirable constituents which are not removed, if they'are not already in such form, will be converted to a form in which they will readily be removed from the unsaponified components present in the fatty material resulting in the production of characteristic undesira'ble tastes and odors in the alkali refined material. Certain hydroxylated compounds, highly unsaturated compounds and amine compounds in fatty materials of. fish origin are aflected detrimentally by the alkali treatment and are converted intoundesira'ol'e constituents which are not effectively removed with the soaps that are formed. I

It is the object of this invention to provide an 1 improved process for the refining of fatty materials. I

' It is a further object 'of this invention to providean improved process for refining vitamincontaining oils of marine origin.

Other objects of theinvention will in part be obvious and-will in part appear hereinafter.

I'have discovered that fatty materials devoid of taste and odor may be obtained by first sapontfying the fatty material to be refined with an amount of alkali sufiicient to saponii'y all of the free fatty acids present in the fatty material and at least two to three per cent of the neutral glycerides, separating the soaps from the unsaponified glycerides, and contacting the unsaponified fatty material with a highly polar solvent immiscible with fattymaterials. The polar solvent will remove taste and odor constituents not removed along with theeoape, and'also a large proportion of any coloring matter contained in the fatty material and not-removed with the soaps. thlll divine a highly desirable bland, odorless, light-colored highly refined material. Also,

" --.in the case of vegetable oils, any 'so-called break" constituents contained therein will be substantially all, removed by the solvent treatment. In most instances it is preferred to saponify between about 5% and about 40% fatty material by the treatment with the highly polar solvent. The process of the invention is particularly applicable for the refining of fatsoluble vitamin-containing marine oils, particulai-ly vitamm-con-taining oils of fish origin. Such oils may be refined very efiectively without hydrolyzing any appreciable portion of the natural vitamin esters contained therein provided the vsap'oniflcation step is carried out as hereinafterdescribed'. Any vitamin alcohols originally present in the oil and the small amount of such alcohols that may be produced by the saponification step, will be removed from the vitamin-containing oil by the extraction with the polar solvent along With the taste and odor constituents and a" large portion of the coloring matter not removed in the saponification step, thus producing a highly refined, bland, odorless, light-colored vitamincontaming oil in which the vitamins are all present in their naturally-occurring ester form. The vitamin alcohols may be readily recovered from the highly polar solvent by any suitable means and employed for purposes for which they are suitable.

Any fatty material which it is desired to improve the taste, color and odor thereof may be refined by'the process of this invention Thus vegetable oils such as cottonseed oil, soybean oil, palm oil, corn oil, corn germ oil, wheat genn oil,

sesame seed oil, teaseed oil, linseed oil, peanut tially all of the natural vitamin esters originally r the fatty mam-n1, preferably from 10% to I 30%,- depending upon the fatty material to be treated, as will appear hereinafter. {thus present therein. I v v It is preferred to employ concentrated aqueous potassium hydroxide for the'alkali refining step; however. any other suitable alkaline sc nts m y cyclohexane, methyl cyclohexane, etc., or a mixture of such solvents. 'Also if desired, a saponification catalyst, e. g. isopropanol, may be employed in the saponification step. When the saponification is carried out in the presence of a solvent, the solvent should comprise from to 99% and preferably to 75% based on t e weisht of the oil. The saponification may be carried out at room temperature or temperatures above room temperature although when vitamin-containing oils are being saponified it is preferred that the saponifioation be carried out at room temperature or slightly above room temperature in order to obtain a rather slow rate of saponification for rea sons as will appear hereinafter.

In the saponification of a non-vitamin-containing oil, the rate of saponification is relatively immaterial: however, in the case of vitamin-containing marine oils, it is preferred that a relatively slow ratev of saponification' be employed since it has been foundthat the natural vitamin esters are not hydrolyzed to any appreciable extent when such conditions of saponification are employed. Thus in saponifying a vita min-containing marine oil it is preferred to carry out the saponification at room temperature either with or without the presence of an inert solvent of the type described above. In some cases when saponifying at room temperature it is desirable to use a catalyst such as isopropanol to bring about the reaction between the fatty material and the alkali. This is particularly true when saponifying in the presence of' a solvent.

The degree of saponification will depend to some extent upon the purpose for which the refined fatty material is to be employed. However, in all instances suflicient alkali should be employed to saponify all .of the fatty acids and at least 2 or 3% of the neutral fatty material triglycerides, and in most cases it is desired that sufficient alkali be used to saponify lbout 10% of the triglycerides. In some instances 'enough alkali may be employed to saponify up to about 40% of the fatty material. In the case of non-vitamin containing Oils which are usually refined for the purpose of obtaining suitable oils for use as salad oils and similar edible purposes, the lower limits of saponification will be employed, since it is desired, of course, not to destroy any more of the oil than necessary. However, in the caseof the refining of the vitamin-containing oils it'may be desirable to saponify up to as high as 40% thereof, since such a degree of saponification may be carried out without hydrolyzing any substantial amount of the natural vitamin esters and thus in addition to refining the oil a certain amount of concentration of the vitamins will be eflected.

After the saponification of the fatty material has been effected, the saponified oil may be separated from the soaps in any suitable manner, e. g. solvent extraction, centrifugation, etc. ably the saponified mass is extracted with a hy- Preferdrocarbon or halogenated hydrocarbon solvent of the aforementioned type. -.l'\he solvent solution of the unsaponified oil is removed'from the soap mass and the solvent removed therefrom to recover the partially refined oil.

The partially refined oil is then contacted with a hi hly polar solvent which is relatively immiscible therewith. The term polar solvent" is employed herein to connote an organic solvent containing a polar functional grouping, i. e. a functional grouping which tends to produce an unbalanced electronic structure and thereby. activate the molecule and import a characteristic dipole moment thereto; examples of such polar functional groupings are the hydroxyl group, the carbonyl group, and the ester grouping.- Such polar solvents which may be used in carrying out the process of the invention include, inter alia, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, acetone, diacetone alcohol, ethyl acetate; methyl acetate, and methyl ethyl ketone,

the last seven named solvents all containing at least 9% of water. Methyl alcohol and ethyl alcohol may contain any suitable quantity of water or no water at all. Suitable mixtures of the above solvents may also be used. The solvents which I-prefer to employ in the practice of the present invention are methyl and ethyl alcohol and 35% to 91% aqueous isopropanol. A solvent sold under the trade-mark Solox by U. B. Industrial Chemicals, Inc. was found to be quite efficacious in practicing this invention. The solvent Solox is prepared by admixing 5 volumes of wood alcohol to every volumes of ethanol and admixing to every 100 volumes of said mix- .the fatty materials are soluble in these solvents at room temperature, whereas the fatty materials themselves are immiscible therewith or relatively so even at higher temperatures.

In carrying out the polar solvent extraction step the partially refined oil is first mixed with the particular solvent to be employed. The relative proportion of solvent to oil may vary widely; the ratio of solvent to oilshould be greater than one and preferably 2 to 50 parts of solvent to 1 part of oil. If desired, the mass may be warmed to a temperature slightly or substantially above room temperature, preferably with agitation. The solvent solution and the fatty material may then be separated from each other at the elevated temperature, or the mixture may first be allowed to cool to room temperature or cooled to a temperature below room temperature before completing this step ofthe process. Furthermore, if desired, a continuous process of extraction may be employed. Preferably the extraction is carried out in an inert gas atmosphere when vitamin oils are being treated.

The oil which has been contacted with the polar ,solvent is thenvfreed of any solvent entrapped therein, and the solvent is also removed from the solvent extract by any, suitable means such -as,'for example, vacuum distillation. The refined oil which is obtained will be bland, odorless and light-colored and in the case of a vitamin-containing oil will contain substantially all of the vitamin esters present inthe original oil. Vegetable 0113 refined by this process will also be substantially free of break constituents. The material which is extracted from the oil with the highly polar solvent will contain taste and odor constituents not removed by the saponification step and a large proportion of the coloring constituents of the unsaponified oil. This fraction will also contain any vitamin alcohols originally n v I present in the fatty material and any vitamin alcohols produced by Example I 100 parts of crude tuna liver oil possessing a strong fishy odor and taste and dark red color were mixed with 3 parts of isopropanol and sufficient 45%.aqueous KOH (4.0 gms.) to saponify about of the oil. The mixture was stirred for 30' minutes and then left at room temperature for 12 hours. The mass was mixed with 400 parts of ethylene dichloride and then filtered. The solvent was removed under reduced pressure from the resulting oil which possessed a slight fish taste and odor, was medium golden yellow in color, and had a characteristic concentrate taste and odor. 75 parts of the alkali treated oil were extracted three times at 18 C. with 300 m1. portions of 98% methanol. The methanol soluble fractions as well as the insoluble fraction were freed of solvent. The methanol soluble fraction possessed a strong fishy and concentrate taste and odor as well as a dark brownish red color. The methanolinsoluble fraction which contained the major portion of the vitamins A and D present in the crude oil was a light'golden yellow and was completely without odor and taste. The vitamins were all present in their natural ester form.

Example II I 300 parts of crude halibut liver oil containing 112,000 I. U. of vitamin A/gm. and having a strong fishy taste and odor were mixed with 9 parts of isopropanol and 150 parts of ethylene dichlorideand then sufilcient 45% aqueous KOH to saponify about 28% of the oil was added. The saponification and the extraction of the unsaponified oil were carried out as in Example I. The resultant oil which had a slight fishy, characteristic concentrate taste and odor and which was rather dark in'color was extracted with methanol as in Example I. The methanol insoluble fraction which had a potency of 139,200 I. U. of vitamin A/gm. and contained about 88% of the vitamin A originally present in the oil, the vitamins being present in their naturally-occurring ester form, was much lighter in color than the partially refined oil and was without taste and odor. The methanol soluble fraction contained most of the taste, odor and color constituents originally present in the crude oil as well as the vitamin alcohols originally present therein, and the small amount of vitamin alcohols produced in the alkali refining step. This fraction which contained about 12% of the vitamin A originally present in the crude oil had a potency of 515,500 I. U. of vitamin m. and was highly suitable for use in the fortification of low potency vitamin-containing oils employed for poultry and animal purposes. Example III 300 parts of shark liver oil containing 157,000 I. U. of vitamin A/gm. and which had a decided fishy taste and odor were refined as in Example II, except that 37.5% of the oil was saponified. A light colored, odorless, bland oil which had a hydrolysisof the vitaminv esters during the partial saponification step.

potency of 222,400 I. U. of vitamin A/gm. and which contained about 87% of the vitamins originally present in the oil was obtained. The vitamins were present in the oil in their naturallyoccurring ester form. The remainder of the vitamins originally present in the crude oil were contained. in the methanol soluble fraction which had a potency of 514,000 I. .U. of vitamin A/gm.

Example IV of along with the major portion of the coloring matter thereof.

' Example V 100 parts of crude tuna liver oil containing 73,000units of vitamin A/gm. and 20,000 units of vitamin D/gm. were mixed with 3 parts of 99% isopropanol and while stirring in the presence of N2 gas sufllcient 45.5% aqueous KOH (4.0 parts) to saponify about 10% ofthe oil was added. After .30 minutes the stirring was ceased and the mass left at room temperature for 3 hours. After adjusting the moisture content of the soap to about 25%, the mass were mixed with 400 parts of ethylene dichloride and the mixture gravity filtered. The clear filtrate was freed of solvent. The resulting oil was greatly improved in color, taste and odor. The alkali treated oil, however, was still slightly fishy and had acquired a slight characteristic concentrate taste and odor. The

' vitamin recovery was substantially 100%.

50 parts of. the above alkali treated oil was mixed with 100 parts of 91% isopropanol and the mixture thoroughly agitated. The mixture was thencooled gradually to .2'l C. and filtered. The insoluble oil was extracted twice more essentially as before- The extracts were combined and freed of solvent. The resulting oil possessed a strong fishy and slight concentrate taste and odor. The alcohol insoluble oil after being freed of. traces of solvent was completely bland and greatly improved in color. The vitamin A and D ester content was essentially the same as that of the crude oil.

Example VI 100 parts of crude soy bean oil were, saponified according to the process of Example I, 10% of the oil being saponified. The unsaponified oil was recovered by extracting the mass with ethylene dichloride and recovering the oil therefrom as before. The alkali treated oil was then extracted I with methanol as in Example I. The refined oil which was obtained was highly satisfactory in all respects 'being light golden yellow in color and free of undesirable tastes, odors and break constituents.

By the process of the invention it is thus possible to produce highly refined fatty materials which are bland, odorless and light-colored; and in the case of vitamin-containing marine oils substantially all of the original vitamin esters are present therein. Oils and fats refined by the process of this invention are applicable for a wide variety of uses.

The phrase continuous extraction is employed in the specification and claims to connote both the usual type of continuous extraction and also what is usually referred to as counter-current extraction.

Selective partial saponiflcation of vitamin-con- Since certain changes may be made in carrying out the above process without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. A process of refining a fatty material comprisingthe steps of saponifying all of the free fatty acids and a minor portion of the glyccrides present in a fat-soluble vitamin-containing marine oil, removing the unsaponified oil from the resulting soap and extracting the soap-free oil with an organic polar solvent immiscible with fatty materials to remove odor, taste and color bodies therefrom.

2. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids and 5% to 40% of the glycerides present in a fat-soluble vitamin-containing marine oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil with an organic polar solvent immiscible with fatty materials to remove odor, taste and color bodies therefrom.

3. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids and 5% to 40% of the glycerldes present in a fat-soluble vitamin-containing marine oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil with methanol to remove odor, taste and color bodies therefrom.

4. A process of refining a fatty material com\- prising the steps of saponifying all of the free fatty acids and 5% to 40% of the glycerides present in a fat-soluble vitamin-containing marine oil, separating the unsaponified oil from the resulting soap and extracting, the soap-free oil with ethanol to remove odor, taste and color bodies therefrom.

5. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids and 5% to 40% of the glycerides present in a fat-soluble vitamin-containing marine oil, separating .the unsaponifled oil from the resulting soap and extracting the soap-free oil with isopropanol containing at least 9% water to remove odor, taste and color bodies therefrom.

6. A process of refining a fatty material comprising the steps of saponifying all *0: the free fatty acids and 10% to 30% of the glycerides present in a fish liver oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil at a relatively low temperature with an organic polar solvent immiscible therewith to remove odor, taste and color bodies therefrom.

' 7. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids and 10% to 30% of the glyoerides present in a fish liver oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil at a relatively low temperature with methanol to remove odor, taste and color bodies therefrom.

8. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids'and 10% to 30% of the glycerides present in a fish liver oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil at a relatively low temperature with ethanol to remove odor, taste and color bodies therefrom. 9. A process of refining a fatty material comprising the steps of saponifying all of the free fatty acids and 10% to 30% of the glycerides present in a fish liver oil, separating the unsaponified oil from the resulting soap and extracting the soap-free oil at a relatively low temperature with propanol containing at least 9% water to re ove odor, taste and color bodies therefrom.

LORAN O. BU'XTON. 

